[skyducker]

It's been a while since I have posted a new thread so bare with me.

I am mainly posting this for the benefit of other members having the same problem.

In the past couple weeks my ride went from a good running mustang to a jerky, surging car I didn't recognize anymore. I only had problems when the car was under a load between 800 and 1800 RPM at normal temperature. No code set at all for this.

I went through the basics:

1. Checked all the connections from the harness to the coils and injectors. All good
2. Checked the boots and noticed a little cracking and white spots. Changed all the boots.
3. Checked the spark plugs, they were a little worn so i changed them.
4. Changed the fuel filter, it has been about 20k or so since the last change.
5. Checked the vacuum lines and connections to their ports. Looked good.

After all this I was confident that everything would run fine, but no, still jerked and surged through the lower RPM. (Ran much better at higher RPM though )

I checked the codes again and nothing showed up.

I did a little research through All Data and came across a Lean Driveability Symptoms bulletin (Article # 98-23-10) that some of the cars have. So I took part of the articles advice and disconnected the MAF to put the car in a FMEM mode ( Failure Mode and Effects Management). In FMEM mode, air flow is inferred by using RPM and throttle position instead of reading the MAF sensor. I disconnected the MAF and drove the car up a hill close by (DO NOT DRIVE THE CAR VERY FAR LIKE THIS). The car didn't drive much different except when trying to get it going from a stop. Then, BAM the check engine light came on. I stopped the car, reconnected the MAF and took it to the shop that was reading my codes (I figured the MAF set off the check engine light). To my surprise a misfire in cylinder 7 caused the light to come on.

We changed the position of the coil to cylinder 5 and tried to get it to set the check engine light again. It wouldn't set the light no matter what we did but still had the problem. At this point I figured it was the coil or the injector but wasn't sure so I found a coil at a recycle yard for $20 bucks. After installing it, it works great and the problem has been solved.

I hope this helps some of you out that may be having a similar issue. From what I understand the original COPS only last around a 100-150k.

As for buying new coils, I was thinking about buying a set of Summit or Acel coils. Anyone have any experience with these?

[BT1288]

I had the same problem, no codes, right at 100,000 miles. I went ahead and replaced all of the c o p's at once. I went with Motorcraft. My mechanic said he's seen cars lose some hp with aftermarket c o p's.